This invention relates to the field of divider circuits. More particularly, it relates to programmable divider circuits particularly but not exclusively suitable for use with display gauges, such as those utilized for displaying engine speed (tachometers), ground speed (speedometers), and distance travelled (odometers). Typically, such gauges are required on motor vehicles including passenger cars, trucks and tractors. Such gauges are important, particularly for trucks and tractors, where lease rates, service intervals and the like are dependent upon mileage while tractors must precisely monitor their ground speed to assure accurate placement of seeds during plowing.
In the past a substantial problem has existed with trucks and tractors when the gearing was changed as, for example, when a truck is in overdrive or when the tire size of a vehicle changes. Electronic measuring devices typically receive their input signals as a series of pulses from the wheel or drive shaft depending upon the condition being sensed. Changing the gear ratio of the final drive of a truck or changing the tire size on the wheels of the vehicle alters the calibration of the speedometer and odometer rendering them inaccurate until re-calibrated. Presently, regardless of the type of instrument employed, re-calibration has been an expensive and time consuming process whereby a skilled mechanic is required to adjust the device for the new operating parameters of tire size or gear ratio.
With respect to the re-calibration necessary for tire size changes and the like, the programmable divider of this invention can be programmed simply by inserting a properly coded key element into a receptacle. The coded key selects the dividing ratio of the programmable divider to account for changes in the condition to be measured.
It is an object of the present invention to provide a programmable divider which can be set by a user to a selected value depending upon the application.
Other objects and advantages of the invention will be apparent from the remaining portion of the specification.